1. Field of the Invention
The present invention relates to a foreign object detection sensor and a method for manufacturing the same, more particularly, to a foreign object detection sensor having a proximity detecting function for detecting whether there is a foreign object in the proximity of a sensor part and a contact detecting function for detecting a contact of foreign object to the sensor part, and a method for manufacturing the foreign object detection sensor.
2. Related Art
As conventional electric sliding door apparatuses for moving and sliding a door panel (movable body) by electrical operation using the drive force of a motor or the like, there are some electric sliding door apparatuses comprising a foreign object detection sensor for detecting a foreign object existing between a peripheral portion of a door opening for passengers and the door panel, so as to prevent insertion of the foreign object between the peripheral portion of the door opening for passengers and the door panel. By way of example only, Japanese Patent Laid-Open No. 11-237289 (JP-A 11-237289) discloses a foreign object detection sensor having a contact detecting function for detecting a foreign object by contacting the foreign object existing between a peripheral portion of a door opening for passengers and a door panel. This foreign object detection sensor as described in JP-A 11-237289 comprises a lengthy sensor part disposed along a front end portion of the door panel, and a pair of electrode wires extending spirally and provided within the sensor part. In addition, a sensor terminal is provided at a lower end portion of the sensor part. The pair of electrode wires are electrically conducted to each other at the sensor terminal via a resistor, and electrically connected to a feeding line (leading wire) connected to a power source via a conductive piece. In such a foreign object detection sensor, electric current flows from one electrode wire to another electrode wire in a normal state where the foreign object does not contact with the sensor part. When the foreign object contacts the sensor part, the sensor part is deformed, so that the pair of electrodes are short-circuited to each other by the contact to the foreign object. As a result, the electric current flows from the one electrode wire to another electrode wire without passing through the resistor, so that an voltage between the pair of electrode wires is increased compared with the normal state. The contact of the foreign object to the sensor part is detected based on variation in voltage.
As the conventional foreign object detection sensors, a foreign object detection sensor having a proximity detecting function for detecting a conductive foreign object in the proximity of a front end portion of a door panel in a non-contact manner in addition to a pressure-sensitive detecting function has been known, as described in Japanese Patent Laid-Open No. 2007-123202 (JP-A 2007-123202). A sensor part of this foreign object detection sensor comprises a pair of electrode wires and a cylindrical detecting electrode provided at an outer periphery of the pair of electrode wires, in which the detecting electrode is connected to a feeding line (leading wire) connected to a power source at a sensor terminal provided at a lower end portion of the sensor part. Such a foreign object detection sensor detects the contact of the foreign object to the sensor part in a similar manner to that of the foreign object detection sensor described in JP-A 11-237289, and detects the proximity of the foreign object to the sensor part based on variation in an electrostatic capacitance between the conductive foreign object in proximity of the sensor part and the detecting electrode.
However, in the foreign object detection sensor having the contact detecting function and the proximity detecting function as described in JP-A 2007-123202, since the electric current is supplied to the detecting electrode as well as the electrode wires, the number of conductive pieces provided at the sensor terminal for the electrical connection with the feeding line. As a result, there is a disadvantage in that wiring structure at the sensor terminal is complicated, which makes interconnection works troublesome.